very high concentrations of sodium carbonate (Na 2 CO 3 ) and
very low level in ions calcium (Ca
2+ ) and magnesium
(Mg
2+ ). Soda lakes and soda deserts are widely distributed
throughout the world (Table 10.3). Soda lakes can be found
in Asia (Turkey, India, China), in Europe (Hungary, exYugoslavia), and in countries of the ex-USSR. The best
studied soda lakes are the lakes of the Rift Valley Eastern
African. Their formation results from the combination of
geological, geographical, and climatic factors: leaching of
the surrounding rocks rich in carbonates by ground and
runoff waters, accumulation in a depression, and high rate
of evaporation. Generation of alkalinity is the result of a
displacement of the balance CO 2 / HCO 3
À / CO 3
2À toward a
dominance of CO 3
2À due to the absence of Ca
2+ . When they
are present, Ca
2+ ions decrease the alkalinity and cause the
precipitation of carbonates in insoluble calcite (CaCO 3 ) as in
the case of brine waters derived from seawater. These waters
generally have high concentrations of calcium ions and have
a neutral pH value, even when being highly concentrated
because the calcium ion concentration always exceeds that
of carbonate. The weakly salted alkaline environments
rarely occur.
Thermal springs with a high calcium content are another
type of highly alkaline natural environment found in different
regions: California, Oman, Cyprus, the former Yugoslavia,
and Jordan. The chemical composition of such waters is
determined by CO 2 -mediated weathering of the calcium and
magnesium minerals such as olivine and pyroxene, which
Table 10.3 Worldwide distribution of natural soda environments (soda lakes and deserts)
Africa
Botswana
Sua salt pan
Libya
Lake Fezzan
Egypt
Wadi El Natrun
Ethiopia
Lake Abjata, Lake Aranguadi, Lake Kilotes, Lake Shala, Lake Chilu, Lake Herlate, Lake Metahara
Sudan
Dariba lakes
Kenya
Lake Bogoria, Lake Nakuru, Lake Elmenteita, Lake Magadi, Lake Simbi, Lake Sonachi
Ouganda
Lake Katwe, Lake Mahega, Lake Kikorongo, Lake Nyamunuka, Lake Munyanayange, Lake Murumuli, Lake
Nunyampaka
Tanzania
Lake Natron, Lake Embagi, Lake Magad, Lake Manyara, Lake Balangida, Basotu, Lake Crate, Lake Kusare, Lake
Tulusia, El Kekhooito, Lake Momela, Lake Lekandiro, Lake Reshitani, Lake Lgarya, Lake Ndutu, Lake Ruckwa
North
Tchad
Lake Bodu, Lake Rombou, Lake Djikare, Lake Momboio, Lake Yoan
North America
Canada
Manito
United States
Alkali Valley, Albert Lake, Soap Lake, Big Soda Lake, Owens Lake, Mono Lake, Deep Springs, Rhodes Marsh,
Soap Lake, Summer Lake, Surprise Lake, Pyramid Lake, Walker Lake
Central America
Mexico
Lake Texcoco
South America
Venezuela
Langunilla Valley
Chili
Antofagasta
Asia
Central Asia
Tuva lakes
Turquie
Lake Van
India
Lake Looner, Lake Sambhar, Lake Lonar, Chilika lagoon, Pangong Lake
China
Dali Lake, Qinghai Hu, Sui-Yian, Heilungkiang, Horsemeno Lake, Kirin, Jehol, Chahar, Shansi, Shensi, Kansu,
Meizhou bay, Tengchong, Xiarinaoer Lake, Yuncheng Lake, Yunnan
Japan
Toyotomi, Iwayama bay (Palau)
Korea
Keusman
Tibet
Lake Soda
Australia
Lake Corangamite, Lake Red Rock, Lake Waerowrap, Lake Chidnup
Europe
Hungary
Lake Fehe ´r, Kelemen-sze ´k, Kiskunsag National Park
Slovenia
Pecena Slatina
Russia
Kulunda Steppe, Lakes Tanatar, Karakul, Araxes lowlands, Chita, Barnaul, Slavgorod
Greenland
Ikka fjord
Ekho Lake (Antarctica),
Sargasoo Sea
386
J.-L. Cayol et al.
very low level in ions calcium (Ca
2+ ) and magnesium
(Mg
2+ ). Soda lakes and soda deserts are widely distributed
throughout the world (Table 10.3). Soda lakes can be found
in Asia (Turkey, India, China), in Europe (Hungary, exYugoslavia), and in countries of the ex-USSR. The best
studied soda lakes are the lakes of the Rift Valley Eastern
African. Their formation results from the combination of
geological, geographical, and climatic factors: leaching of
the surrounding rocks rich in carbonates by ground and
runoff waters, accumulation in a depression, and high rate
of evaporation. Generation of alkalinity is the result of a
displacement of the balance CO 2 / HCO 3
À / CO 3
2À toward a
dominance of CO 3
2À due to the absence of Ca
2+ . When they
are present, Ca
2+ ions decrease the alkalinity and cause the
precipitation of carbonates in insoluble calcite (CaCO 3 ) as in
the case of brine waters derived from seawater. These waters
generally have high concentrations of calcium ions and have
a neutral pH value, even when being highly concentrated
because the calcium ion concentration always exceeds that
of carbonate. The weakly salted alkaline environments
rarely occur.
Thermal springs with a high calcium content are another
type of highly alkaline natural environment found in different
regions: California, Oman, Cyprus, the former Yugoslavia,
and Jordan. The chemical composition of such waters is
determined by CO 2 -mediated weathering of the calcium and
magnesium minerals such as olivine and pyroxene, which
Table 10.3 Worldwide distribution of natural soda environments (soda lakes and deserts)
Africa
Botswana
Sua salt pan
Libya
Lake Fezzan
Egypt
Wadi El Natrun
Ethiopia
Lake Abjata, Lake Aranguadi, Lake Kilotes, Lake Shala, Lake Chilu, Lake Herlate, Lake Metahara
Sudan
Dariba lakes
Kenya
Lake Bogoria, Lake Nakuru, Lake Elmenteita, Lake Magadi, Lake Simbi, Lake Sonachi
Ouganda
Lake Katwe, Lake Mahega, Lake Kikorongo, Lake Nyamunuka, Lake Munyanayange, Lake Murumuli, Lake
Nunyampaka
Tanzania
Lake Natron, Lake Embagi, Lake Magad, Lake Manyara, Lake Balangida, Basotu, Lake Crate, Lake Kusare, Lake
Tulusia, El Kekhooito, Lake Momela, Lake Lekandiro, Lake Reshitani, Lake Lgarya, Lake Ndutu, Lake Ruckwa
North
Tchad
Lake Bodu, Lake Rombou, Lake Djikare, Lake Momboio, Lake Yoan
North America
Canada
Manito
United States
Alkali Valley, Albert Lake, Soap Lake, Big Soda Lake, Owens Lake, Mono Lake, Deep Springs, Rhodes Marsh,
Soap Lake, Summer Lake, Surprise Lake, Pyramid Lake, Walker Lake
Central America
Mexico
Lake Texcoco
South America
Venezuela
Langunilla Valley
Chili
Antofagasta
Asia
Central Asia
Tuva lakes
Turquie
Lake Van
India
Lake Looner, Lake Sambhar, Lake Lonar, Chilika lagoon, Pangong Lake
China
Dali Lake, Qinghai Hu, Sui-Yian, Heilungkiang, Horsemeno Lake, Kirin, Jehol, Chahar, Shansi, Shensi, Kansu,
Meizhou bay, Tengchong, Xiarinaoer Lake, Yuncheng Lake, Yunnan
Japan
Toyotomi, Iwayama bay (Palau)
Korea
Keusman
Tibet
Lake Soda
Australia
Lake Corangamite, Lake Red Rock, Lake Waerowrap, Lake Chidnup
Europe
Hungary
Lake Fehe ´r, Kelemen-sze ´k, Kiskunsag National Park
Slovenia
Pecena Slatina
Russia
Kulunda Steppe, Lakes Tanatar, Karakul, Araxes lowlands, Chita, Barnaul, Slavgorod
Greenland
Ikka fjord
Ekho Lake (Antarctica),
Sargasoo Sea
386
J.-L. Cayol et al.